The present invention relates to a device, which in its most commonly occuring but not critical practice is generally laid "underground", although not limited thereto. The inventive device is set up to warn of any disturbance, whether temporary or otherwise, resulting from the application of a moving or stationary gravity load. The device of this invention would be typically utilized to issue warning signals on heavy masses passing by it. The present invention relates generally to related circuitry (known per se) for operating the device.
Known in the pertinent art are, as far as the Inventors are aware, devices of the same type as specified above or their equivalents. For example, various arrangements are known which are based on detection of capacitive changes, which arrangements may, for instance, include at least one pair of conductors positioned at a suitable distance apart and being jointly effective to issue a signal. For example, a means is known, such as pressurized tubes, which are responsive to pressure changes or other phenomena, and occasionally also to vibratory states. In the same field of this invention, for example, a means is known, but not limited thereto, which falls within the class of so-called "inertial sensors", seismic sensors, geophones, and the like.
Such prior means may utilized a variety of phenomena, such as a change in the amplitude of the frequency being received, a pressure change which is detected by a pipe system containing a high pressure liquid, and systems associated with suitable piezoelectric sensors. Also known are seismic sensors which are practically inertial systems and detect mass movements to issue electric signals.
Such prior means or systems are subjected to a number of limitations concerning their installation, and the electronic or non-electronic picking up and/or handling of the detected signals. A further limitation as, for example, is the practical impossibility of recognizing or discriminating a seismic wave which may be originated far away from a more local mass movement, which would only justify a signal proper or emergency warning.